Abstract: The principle of calculating, with finite element method, the cyclic variation of wall temperature in internal combustion engine and its program design are introduced in this paper. The program design has been used, with one dimensional mode of heat tromsfer, to calculate the cyclic variation curve of wall temperature in cumbustion head of 285QB diesel engine. It is shown that the conclusion made from this calculation method is in line with the relevant law. The method can be used to calculate the cyclic variation of the wall temperature in internal combustion engine according to two dimensional and three dimensional heat transfer mode.